Fluid bearings have been used for some time for the transport of heavy or extremely bulky objects. An advantage of the fluid bearing lies in the fact that it may be placed beneath an object and it can, when inflated, transport that object without the requirement of raising the object a great distance from the supporting surface or requiring specialized equipment. An object may thus be moved with little overhead clearance and it is only necessary that the object be capable of sitting upon a platform or cradle which may be supported by the fluid bearing.
One of the difficulties with fluid bearings heretofore known, lies in the fact that if the bearing is inflated to a relative high pressure with respect to the pressure within the plenum, the bearing has a tendency to hop leading to instability. Another difficulty with the air bearing lies in the fact that if the bearing is not properly inflated and the plenum is overpressurized, the bearing does not have sufficient flexibility and give to absorb the slight, irregularities of a supporting surface. Still a further difficulty with currently existing bearings lies in the fact that overpressurization of the bearing causes stress wrinkles in the fabric causing areas of excess wear and further affects the uniform flow beneath the bearing surface. An operator would tend to overinflate a bearing when using a surface having unacceptable roughness, for example unsealed concrete, in an attempt to increase the flow beneath the bearing surface.
In an effort to overcome these basic deficiencies, which are evident in the patent to Crowley, U.S. Pat. No. 3,513,936, issued May 26, 1970, an improvement was presented as evidenced by U.S. Pat. No. 3,618,694 issued Nov. 9, 1971 which through the use of a dam like structure, restricted the flow into the plenum until the bearing was at least partially inflated.
With the above noted problems in mind, it is an object of the present invention to provide an improved fluid bearing which, because of its particular structure and because of the method of providing fluid under pressure achieves a proper and uniform inflation of the bearing independent of pressurization of the plenum.
It is another object of the present invention to provide a means for assuring proper pressurization of the bearing and the plenum by means of an inexpensive and simple conduit configuration.
Yet another object of the present invention is to provide a unique means for securing a fluid bearing to its overlying plate or pallet member.
A still further object of the present invention is to provide a fluid bearing which regulates the fluid entering the bearing and diverts the majority of fluid to the plenum to provide greater separation from the operating surface.
Another object of the present invention is to provide a bearing wherein the fluid flow to the plenum and the airbag is carefully controlled permitting high inflation of the plenum and without overly inflating the airbag.
Yet another object of the present invention is to provide separate controls for a fluid bearing such that the relative flow to each may be carefully controlled and selectively terminated.
Still a further object of the present invention is to provide an air bearing including means to control the inflation such that the bearing may be successfully inflated in an unloaded condition under special circumstances.